Ore concentration.



UNITED STATES PATENT OFFICE.

GEORGE ALBERT CHAPMAN AND STANLEY TUCKER, OF LONDON, ENGLAND, ASSIGN- ORS '10 MINERALS SEPARATION LIMITED, OF LONDON, ENGLAND.

ORE CONCENTRATION. 7

No Drawing.

Specification of Letters Patent.

To all whom it may concern Be it known that we, GEORGE ALBERT CHAPMAN and STANLEY TUoKER, subjects of the King of England, both residing in London, England, have invented certain new and useful Improvements in Ore Concentration, of which the following is a specification.

This invention is for. improvements in or relating to ore concentration and has partic'; ular reference to the now well-known flotation processin which ore is agitated in water containing certain agents, in such a way that when the pulp is brought into a spitzkasten or the like a froth-floats to the surface carrying certain constituents of the ore such as metallic sulfids. Hitherto in carrying out such processes it has been the common practice to mix the powdered ore with about four times its weight of water and to add to the pulp a small quantity of sulfuric acid (for example 1% on the weight of ore) and also to add to the pulp a very small proportion of either an immiscible oily agent such as oleic acid, Texas fuel oil, etc., or of a soluble mineral-frothing agent such as phenol, cresol, amly alcohol, amyl acetate, etc., all as described for example in prior United States Patents No. 835,120, of November 6,1906, No. 955,012, of April 12, 1910, and 962,678,- of June 28, 1910, and British Patents No. 18,947 of 1910 aha No. 21,857 of 1910. Another common practice has been to utilize inthe above process as the frothing agent mixtu es. of different mineral frothing agents both oily or immiscible and soluble. In some cases the sulfuric acidv above referred to is omitted; and the above processes are commonly practised at various temperatures varying from ordinary atmospheric temperatures up to say 60 C. or even higher,

As stated in these earlier patents the condit'ions most suitable and economical for the treatment of a particulart ore are best determined by a simple preliminary trial.

In some cases the ore is submitted to a wet.- crushing process and after removal of part of the water used in crushing the'pulp is run straight to the flotation plant. In some instances, as disclosed in United States Let- Application filed December 26, 1912. Serial No. 738,586.

agents referred to out of cont-act with the ore, or in other words the ore and agents and the water (with or without sulfuric acid) have been all agitated together.

-In the course of careful investigations-on certain ores it has been found that the efficlency of the process e. the recovery of concentrates or the gra e of the concentrates or both) may be greatly improved by agitation of the water .with one or more agents of the kind referred to before the agitation of the powdered ore with the water or before the addition of the ore to the water, and such agents as those used will'be hereinafter referred to as modifying agents-for example if the water be first agitated with a minute proportion of such agent after which the ore and further quantities of suitable agent be added to the treated water and agitated, a mineral-bearing froth is formed in the usual way. If necessary sulfuric acid, bisulfate of soda or equivalent may be added to the water or pulp at any stage or such addition may be dispensed with.

Before discussing the various factors which appear tocontribute to the success of this invention a few examples of its application will be given.

Example 1: A chaloopyrite ore containing 2.33% copper was crushed to 80 mesh.

A quantity of Water equal to four times the sene oil were added. The vigorous agitation was continued in the well'known manner necessary for the production of a mineral-bearing froth and when the pulp was brought to a state of comparative rest' the floating froth formed and was removed. The concentrates showed a recovery of 7 7 .5% of the copper with a grade of 12.4% of copper.

Example 2: The same ore was crushed to the same mesh. A quantity of water of .about four times the weight of the ore to be treated was introduced into the agitation vessel and agitated with 0.022% of. cresol (pure cresylic acid), as before and to the water thus treated was added the ore together with 0.13% of Texas fuel oil and 0.01% ofwood tar oil. The mixture of. ore, Water andreagents was then vigorously agitated in the well known manner necessary.

for the production of a mineral bearing froth and the froth was removed. The concentrates showed a recovery of 86.5% of the copper with a grade of 9.55% of copper.

' centrate showing a recovery of 7 3% of copper with a grade of 7.98% of copper. This clearly indicates that the preliminary treatment of thewater greatly improved both the recovery and the grade of the concentrates.

Example 3: The same ore so crushed to the same mesh. A quantity of water four times the weight of the ore to be treated was introduced into the agitation vessel and agitated with 0.009% on the ore. of oil of eucalyptus and to the water thus treated was I added the oretogther with 0.13% of Texas fuel oil and 0.009% on the ore of wood tar oil. .The mixture of ore, water and reagents was then vigorously agitated in the well known manner for the production of a mineral bearing froth, which was removed. The tailings were reagitated and a floating froth which formed was removed and added to the concentrates. The concentrates showed a recovery of 87.5% of the copper with a grade of 10.86% of copper. A similar test in which the water received no preliminaryftreatment and in which the eucalyptus was added with the Texas fuel oil and wood tar oil to the oreand water, gave a concentrate having a recovery of 73% of the copper with a grade of 6.19% of copper. Example 1: A chalcopyrite or containing 2.02% of copper was treated in the apparatus usually employed for carrying the froth flotation process into efiect, namely that described in the previous United States Patent No. 979587 in which the ore is agitated with water and a mineral frothing agent in an agitation 'box and thereafter discharged into a spitzkasten where the froth formed floats, the tailings from the spitzkasten being then drawn'into a second agitation box and reagitated and discharged into a second spitzkasten and so on.- In the case of the present example, the water was agitated in the first mixer with 0.5 lbs.

. per ton of ore (0.022%) ofcresol and assed direct to the second mixer where e ore crushed to.80 mesh Was introduced. The ore and water passed immediately from the second mixer to the third mixer where 2.7 lbs. per ton of Texas fuel oil (0.12%) and 0.22 lbs. per ton of ore of wood' tar oil (0.019%) were added. After agitation in the third box the mixture of ore and water and frothing agents was discharged into a spitzkasten, the tailings being returned to I a forth mixer where a further 0.6 lbs.per ton of Texas fuel oil (0.027%) and 0.09 lbs. per'ton (0.004%),of wood tar oil were added. Similar quantities were added in the fifth mixer. and at atmospheric temperature. The result of the treatment was as follows :The first concentrates contained 14.11% of copper,

the second concentrates 8.8% of copper and the residues 0.26% of copper, giving a re-.

centration, but it is found that if the water,

be submitted to the preliminary treatment with the modifying agent as described, this The circuit was non-acid tendency is-diminished or obviated. Where I the ore (generally'the gangue) .contain's acid-consumers such as easily decomposable carbdnates the ordinary process may not be applicable, but by using this invention in many cases sulfuric acid or its usual equivalents may be dispensed with and good, highgrade concentration can be obtained. The

process is also specially applicable to ores.

containing. gangues which are readily oiled or where there are non-floatable metalliferous constituents such as oxidized minerals. These oxidized minerals in the usual way interfere with the separation of the metalliferous particles, but in 'this process they do not interfere with the subsequent formation of a clean concentrate. Itwill be seen that this process involves the use of two agents .viz. the first agent added to the water alone and acting as amodifying agent and the second or frothing agent which is added to the ore pulp and agitated therewith. in the usual way.

The substances suitable for use as modifying agents are essential oils, such as eucalyptus, phenol,- cresol, amyl-alcohol, amylacetate, wood tar oil, wood alcohol and the like and mixturescontaining them. These are used in minute quantities such as from 0.001% .to. 0.1% on the weight of ore. The modifying agent alters the internal molecular physical orcapillary properties of the water and it is found that generally the modifying agents are such as, on vlolent agitation with water bring about an emulsifi-cation'of air in the" water, 2'. e. such a minute subdivision of the air as to render the water milky for an appreciable time.

The frothing agents are any of the min- I .eral frothing agents hitherto employed in of eucalyptus,

the flotation processes, or mixtures of these, generally about 0.002% to 0.4% of the weight of the ore. When a mixture is employed as the frothing agent, the lighter part thereof is preferably amyl acetate, oil wood tar oil, amyl alcohol, American turpentine or similar substance, and as the heavier part, Texas fuel oil, oleic acid and Russian crude petroleum have been found to be suitable. In certain cases it is found that the same oil may be used as the modifying agent and as the lighter part of a mixture for the frothing agent.

Allowing the water after treatment with the modifying agent to stand appears to be beneficial rather than otherwise, to the results, and in this connection it has been found that the water from one test may be used'aga-in for other tests. It is found that the preliminary agitation of the water with the minute proportion of modifying agent enables a much smaller proportion of frothing agent to be used than is otherwise necessary. The above process can be made continuous in any of the usual ways. If water which has been used in the'flotation process is again used therein, this circuit water may be flowed into the first mixer of the flotation plant and there agitated out of contact with the ore, While the ore pulp containing such a proportion of water as will produce, when mixed with the circuit water, the desired degree of dilution of the pulp may be flowed into the second mixer. If it should be found that the circuit water contained sufiicient modifying agent, no further addition of modifying agentwould be required in the first mixer or prior thereto, but otherwise a sufficient quantity of modifying agent would be added to the circuit water either in the first mixer or before it entered the first mixer. Such procedure would be substantially as described'in the fourth example above given, and the froth ing agent would be added either in the second mixer or in later mixers, or in the second and one or more later mixers, as should be found most suitable and economical with the agent used and the ore under treatment.

What we claim as our invention and desire to secure by Letters Patent is I 1. A process for concentrating ores, which consists in first agitating a quantity of water with a modifying agent out of contact with the ore so as to form an air emulsion and thereafter adding to the water the ore to be treated and a itating the same therewith so as to form a froth and separating the froth.

2. A process for concentrating ores, which consists in first agitating a quantity of water with a modifying agent out of contact with the ore so as to form an air emulsion and thereafter adding to the water the ore to be treated together with a mineralfrothing agent and agitating the same therewith so as to form a froth and separating the froth.

3. A process for concentrating ores, which consists in first violently agitating a' quantity of water with an air-emulsifying agent out of contact with the ore and thereafter adding to the water the ore to be treated and agitating the same therewith so as to form a froth and separating the froth.

4. A process for concentrating ores, which consists in first violently agitating a quantity of water with an air-emulsifying agent out of contact with the ore and thereafter adding to the water the ore to be treatedtogether with a mineral-frothing agent and agitating the same therewith so as to form a froth and separating the froth.

5. A process for concentrating ores, which consists in first agitating a quantity of water with cresol out of contact with the ore so as to form an air emulsion and thereafter adding to the water the ore to be treated and agitating the same therewith so as to forma froth and separating the froth.

6. A process for concentrating ores, which consists in first agitating a quantity of water with cresol outof contact with the ore so as to form an air emulsion and thereafter adding to the water the ore to .be treated together with a mineral-frothing agent and agitating the same therewith so as to form a froth and separating the froth.

7. A process for concentrating ore, which consists in first agitating a quantity of water with cresol out of contact with the ore so as to form an air emulsion and thereafter adding to the water the ore to be treated together with a small proportion of oil and agitating the same therewith so as to form a froth and separating the froth.

8. A process for concentrating ores, which consists in first agitating a quantity of water with cresol out of contact with the ore so as to form an air emulsion and thereafter adding to the water the ore to be treated together with a small proportion of a mixture of Texas fuel oil and wood tar oil and agitating the same therewith so as to form a froth and separating the froth.

In testimony whereof we have signed our names to this specification in the presence of two subscribing witnesses.

GEORGE ALBERT CHAPMAN. STANLEY TUCKER. Witnesses:

J. WILLIAMS, E. J. WORTH. 

